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[ARCHIVED THREAD] - Phase converter options (Page 1 of 2)
Posted: 11/1/2016 11:47:22 AM EDT
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I have a 60's vintage Bridgeport with a 1hp motor and change-belts that needs 3-Phase.
I hope to add a surface grinder in the near future that will also need 3-phase, and someday upgrade my lathe. Right now I am considering a 3hp AC tech phase converter. Any other possibilites I may be overlooking? http://shop.actechdrives.com/AC-Tech-Lenze-ESV222N02YXB-p/esv222n02yxb.htm All this 3-phase, Phase Coverter talk is Greek to me, and have to rely on the advice of people who know more about this stuff than I do. So any help would be great. |
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I have two Bridgeports. And went with a variable frequency drive perhaps a bit more modest than the one you mention in your post. TECO FM50. Was less than $150 on eBay.
Just recently bought a 3HP table saw - 3phase - that needs a VFD bigger than the TECO. $135 off eBay. Chinese special. Am programming it now. I'm sure it will work. Ray |
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I have two Bridgeports. And went with a variable frequency drive perhaps a bit more modest than the one you mention in your post. TECO FM50. Was less than $150 on eBay. Just recently bought a 3HP table saw - 3phase - that needs a VFD bigger than the TECO. $135 off eBay. Chinese special. Am programming it now. I'm sure it will work. Ray Can't believe I didn't say that. A vfd will do the phase conversion provided you size the vfd properly for that app. |
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VFD's are cheap enough to make rotary phase converters obsolete, and they're helluva lot more quiet. We did two recently, the VFD's are a little over $100 on eBay and are a GREAT solution... See: http://www.ar15.com/forums/t_1_139/1923019_230_460V_electric_motor_wiring_question.html&page=1#i62673645 |
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My Bridgeport mill runs off a Lenze AC Tech VFD/Phase converter plugged into a 220V 1PH outlet. IIRC it was around $200
Call Wolf Automation they can hook you up with the best VFD for your application. |
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Quoted: Those TECO VFD's are great, especially for the price. I have a 120V 1ph to 460v 3ph for my lathe motor and a 220V 1ph to 220V 3ph for my live tooling spindle. Definitely quiet and convenient for speed control. You may have it wired that way, I assure you that is not what is happening. Only way you can get 460 out of 110 is with a transformer. |
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You may have it wired that way, I assure you that is not what is happening. Only way you can get 460 out of 110 is with a transformer. Quoted:
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Those TECO VFD's are great, especially for the price. I have a 120V 1ph to 460v 3ph for my lathe motor and a 220V 1ph to 220V 3ph for my live tooling spindle. Definitely quiet and convenient for speed control. You may have it wired that way, I assure you that is not what is happening. Only way you can get 460 out of 110 is with a transformer. This... |
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If you use a VFD or a rotary phase converter to turn 110 to 3 phase, if you wire the three phase together you will get 460v (depending on how you wire it). Three phase is essentially 3x 110v line anyways (obviously at a different phase). Would you be more clear about this... Details... References... |
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If you use a VFD or a rotary phase converter to turn 110 to 3 phase, if you wire the three phase together you will get 460v (depending on how you wire it). Three phase is essentially 3x 110v line anyways (obviously at a different phase). There may be some more expensive VFDs that can convert 1ph 115V to 3ph 460, however, in my experience, they only double the voltage once the phase is converted. I'm not an electrician, but have looked over quite a few VFD Electrical Control Wiring Diagrams and specification sheets. |
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Yeah, lower HP rated units commonly can increase the voltage from 120 to 240, but I've never seen one go higher than that. They seem to get pretty pricey and uncommon when you get over 1HP and need 240 from 120.
VFD's are the way to go for sure. The 3 phase motors are so smooth and the adjustable speed is so much nicer than changing belts. If I ever have a single phase motor go out on any of my heavier tools, it's getting replaced with a 3 phase and a VFD. |
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Yeah, lower HP rated units commonly can increase the voltage from 120 to 240, but I've never seen one go higher than that. They seem to get pretty pricey and uncommon when you get over 1HP and need 240 from 120. VFD's are the way to go for sure. The 3 phase motors are so smooth and the adjustable speed is so much nicer than changing belts. If I ever have a single phase motor go out on any of my heavier tools, it's getting replaced with a 3 phase and a VFD. I did that, replacing a single phase 220v motor with a 3 phase and a VFD on an 11x36 lathe. I got rid of the 1 hp old motor and 75 lbs of 1950's speed control with countershafts and a snowmachine belt for speed control, and went with a 3 HP motor for low end torque. I wanted smooth low speed and a mid range topspeed, so I sheaved it that way and used link belts. Man, that is smooth. My first slow speed finish job on aluminum looked like a mirror. It took away a vibration telegraphing through my headstock onto a finished part. Go VFD, and you will never go back. To adjust speed, just twirl on a 10k pot and pick your readout of frequency or motor amps. You can probably program an arduino to give you feet per minute of cutting speed, but I have not put any thought into it. None of this unlock, puuuuull the lever and lock it back and hope for the best nonsense anymore. If I ever bought another Bridgeport, I would look for an older one with the exposed belts and VFD that. BTW, 220v "single phase" is two 110V single phases 120 degrees out of phase. 220V three phase is like it sounds, three phases 120 degrees apart. 460/600V is an entirely different voltage standard. |
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I did that, replacing a single phase 220v motor with a 3 phase and a VFD on an 11x36 lathe. I got rid of the 1 hp old motor and 75 lbs of 1950's speed control with countershafts and a snowmachine belt for speed control, and went with a 3 HP motor for low end torque. I wanted smooth low speed and a mid range topspeed, so I sheaved it that way and used link belts. Man, that is smooth. My first slow speed finish job on aluminum looked like a mirror. It took away a vibration telegraphing through my headstock onto a finished part. Go VFD, and you will never go back. To adjust speed, just twirl on a 10k pot and pick your readout of frequency or motor amps. You can probably program an arduino to give you feet per minute of cutting speed, but I have not put any thought into it. None of this unlock, puuuuull the lever and lock it back and hope for the best nonsense anymore. If I ever bought another Bridgeport, I would look for an older one with the exposed belts and VFD that. BTW, 220v "single phase" is two 110V single phases 120 degrees out of phase. 220V three phase is like it sounds, three phases 120 degrees apart. 460/600V is an entirely different voltage standard. Quoted:
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Yeah, lower HP rated units commonly can increase the voltage from 120 to 240, but I've never seen one go higher than that. They seem to get pretty pricey and uncommon when you get over 1HP and need 240 from 120. VFD's are the way to go for sure. The 3 phase motors are so smooth and the adjustable speed is so much nicer than changing belts. If I ever have a single phase motor go out on any of my heavier tools, it's getting replaced with a 3 phase and a VFD. I did that, replacing a single phase 220v motor with a 3 phase and a VFD on an 11x36 lathe. I got rid of the 1 hp old motor and 75 lbs of 1950's speed control with countershafts and a snowmachine belt for speed control, and went with a 3 HP motor for low end torque. I wanted smooth low speed and a mid range topspeed, so I sheaved it that way and used link belts. Man, that is smooth. My first slow speed finish job on aluminum looked like a mirror. It took away a vibration telegraphing through my headstock onto a finished part. Go VFD, and you will never go back. To adjust speed, just twirl on a 10k pot and pick your readout of frequency or motor amps. You can probably program an arduino to give you feet per minute of cutting speed, but I have not put any thought into it. None of this unlock, puuuuull the lever and lock it back and hope for the best nonsense anymore. If I ever bought another Bridgeport, I would look for an older one with the exposed belts and VFD that. BTW, 220v "single phase" is two 110V single phases 120 degrees out of phase. 220V three phase is like it sounds, three phases 120 degrees apart. 460/600V is an entirely different voltage standard. 180 degrees out of phase? 
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Yeah, lower HP rated units commonly can increase the voltage from 120 to 240, but I've never seen one go higher than that. They seem to get pretty pricey and uncommon when you get over 1HP and need 240 from 120. VFD's are the way to go for sure. The 3 phase motors are so smooth and the adjustable speed is so much nicer than changing belts. If I ever have a single phase motor go out on any of my heavier tools, it's getting replaced with a 3 phase and a VFD. VFD's are cheap enough to convert every single phase tool you have. 3 phase motors are almost free. I want to add one to my band saw. I have seen a couple of set ups that shared the VFD. I have been curious about the 110VAC single phase to 220V three phase VFD's, but I bet I'll still need 20 amp service. |
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If you use a VFD or a rotary phase converter to turn 110 to 3 phase, if you wire the three phase together you will get 460v (depending on how you wire it). Three phase is essentially 3x 110v line anyways (obviously at a different phase). Please tell me you don't do anything remotely involving electricity? Or wiring? Or...anything at all, really? |
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Hard starting motors like gear head lathes will require a rotary phase converter. Using a VF you won't get the full power needed. lol Once the lathe is started and running... "What difference does it make?" VFC's can easily be programmed to start slowly and run up, requiring less current... Soft start... |
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Quoted:Motor will likely last 3 times as long by significantly reducing the starting stresses... Quoted:Motor will likely last 3 times as long by significantly reducing the starting stresses... Absolutely. Every one of our tank agitators gets either a soft start or VFD, for this reason. Quoted:
I have been curious about the 110VAC single phase to 220V three phase VFD's, but I bet I'll still need 20 amp service. Going to depend on FLA draw. Which will be a factor of design and OA HP. My lathe motor is on a 20A circuit, but draws under 3A at full load. My drill press and bench grinder are on the same circuit as I'll only use 1 at a time. |
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Quoted: Hard starting motors like gear head lathes will require a rotary phase converter. Using a VF you won't get the full power needed. VFD's come in two 'flavors' with some that can perform both roles ... constant torque and variable torque. Variable torque is used in sucking and blowing applications; pump and fan. Low speed, low torque - high speed, high torque. Benefit? Energy savings, 80% speed will give you 50% energy savings. Constant torque will provide full torque on a zero speed reference. Think elevators, cranes and conveyor belts. When you tell it to stop at zero speed, you don't want it to move backwards. Anything with a gearbox requires a constant torque drive. All VFD's have the same "guts" ... what you are paying for in the higher priced units is the logic/firmware that controls and protects the motor. No reason to use a rotary converter unless you need the voltage. It still is very inefficient. |
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Guys, stop embarrassing yourselves. This thread is like talking to a knitting club about guns.
One of the very nice things about a VFD is you can program the ramp up time. Instead of starting a single phase motor at 1800 rpm, the VFD will slowly start it with a linear increase in speed in 3 seconds or so (what ever you program it for). This really cuts down on the "FLA" required to start a motor. This can be important if you are starting a large chuck at high speed or have a heavy piece of work on the lathe. Another nice thing is you can put, say a 5 hp motor on a 15 amp circuit, and limit the amp draw by programming the VFD - maximum amps, and slowly starting and stopping the motor. The VFD itself draws only 50-75 watts of power.  No, Single phase 220v is two 110V single phase lines 120 degrees out of phase.
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Quoted:
Guys, stop embarrassing yourselves. This thread is like talking to GD about guns.  FIFY
One of the very nice things about a VFD is you can program the ramp up time. Instead of starting a single phase motor at 1800 rpm, the VFD will slowly start it with a linear increase in speed in 3 seconds or so (what ever you program it for). This really cuts down on the "FLA" required to start a motor. This can be important if you are starting a large chuck at high speed or have a heavy piece of work on the lathe. No, Single phase 220v is two 110V single phase lines 120 degrees out of phase.OMG! "No, Single phase 220v is two 110V single phase lines 120 degrees out of phase" I think 180 degrees is what is meant... "One of the very nice things about a VFD is you can program the ramp up time. Instead of starting a single phase motor at 1800 rpm, the VFD will slowly start it with a linear increase in speed in 3 seconds or so (what ever you program it for). This really cuts down on the "FLA" required to start a motor. This can be important if you are starting a large chuck at high speed or have a heavy piece of work on the lathe." In the context of this topic, we're talking about starting/running 3 phase motors with 3 phase VFD's ***************************** This said I have experimented with inexpensive VFD's similar to the one in the link I posted on the other page... And did successfully run a 240 vac single phase [capacitor] furnace blower motor similar to what anyone would have in their home... The motor ran nicely and the total power draw was similar to running it on 240 ac. The VFD allowed the speed to be easily changed and the energy consumption was pretty much what I expected during less blower load tests. No over-heating or other ill symptoms... |
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Quoted: Even single speed motors that are not Inverter rated? Every motor in large units or pumps that we replace that are VFD controlled we use rated motors. Have not seen long term data on non rated motors being used so I can't say with 100% accuracy. The major difference with inverter duty and non-inverter duty motors is they use class H insulated wire for the windings. There are many rebuilt motors that are fifty+ years old running on drives because of higher quality windings that resist heat better. The other issue to consider when using VFD's is motor bearing failure caused by currents induced by the simulated sine wave that is really a pulse width modulated square wave. This is mitigated by using VFD rated shielded motor leads with the proper grounding connectors and/or Aegis motor shaft grounding rings and/or ceramic bearings ... With all three used together being the best option. But nobody wants to pay for that. Bottom line, it depends how expensive your downtime is. |
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The major difference with inverter duty and non-inverter duty motors is they use class H insulated wire for the windings. There are many rebuilt motors that are fifty+ years old running on drives because of higher quality windings that resist heat better. The other issue to consider when using VFD's is motor bearing failure caused by currents induced by the simulated sine wave that is really a pulse width modulated square wave. This is mitigated by using VFD rated shielded motor leads with the proper grounding connectors and/or Aegis motor shaft grounding rings and/or ceramic bearings ... With all three used together being the best option. But nobody wants to pay for that. Bottom line, it depends how expensive your downtime is. Quoted:
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Even single speed motors that are not Inverter rated? Every motor in large units or pumps that we replace that are VFD controlled we use rated motors. Have not seen long term data on non rated motors being used so I can't say with 100% accuracy. The major difference with inverter duty and non-inverter duty motors is they use class H insulated wire for the windings. There are many rebuilt motors that are fifty+ years old running on drives because of higher quality windings that resist heat better. The other issue to consider when using VFD's is motor bearing failure caused by currents induced by the simulated sine wave that is really a pulse width modulated square wave. This is mitigated by using VFD rated shielded motor leads with the proper grounding connectors and/or Aegis motor shaft grounding rings and/or ceramic bearings ... With all three used together being the best option. But nobody wants to pay for that. Bottom line, it depends how expensive your downtime is. Partly correct... IIRC, there are small inexpensive 3 phase reactors that can help with the issues you mention... By smoothing the sq wave PWM... Again, in the context of this topic, aren't we talking about non-commercial hobby use? The winding failure issue IIRC, is not HEATING of the motor windings, but voltage breakdown of the insulation due to the inherent spikes associated with square waves... That series inductance/reactance in the phase legs can reduce... The motors with VFD's run cool, generally, this is one of the advantages of VFD's. |
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Quoted: OMG! "No, Single phase 220v is two 110V single phase lines 120 degrees out of phase" I think 180 degrees is what is meant... "One of the very nice things about a VFD is you can program the ramp up time. Instead of starting a single phase motor at 1800 rpm, the VFD will slowly start it with a linear increase in speed in 3 seconds or so (what ever you program it for). This really cuts down on the "FLA" required to start a motor. This can be important if you are starting a large chuck at high speed or have a heavy piece of work on the lathe." In the context of this topic, we're talking about starting/running 3 phase motors with 3 phase VFD's ***************************** This said I have experimented with inexpensive VFD's similar to the one in the link I posted on the other page... And did successfully run a 240 vac single phase [capacitor] furnace blower motor similar to what anyone would have in their home... The motor ran nicely and the total power draw was similar to running it on 240 ac. The VFD allowed the speed to be easily changed and the energy consumption was pretty much what I expected at less blower load. No over-heating or other ill symptoms... Quoted: Quoted: Guys, stop embarrassing yourselves. This thread is like talking to GD about guns. FIFYOne of the very nice things about a VFD is you can program the ramp up time. Instead of starting a single phase motor at 1800 rpm, the VFD will slowly start it with a linear increase in speed in 3 seconds or so (what ever you program it for). This really cuts down on the "FLA" required to start a motor. This can be important if you are starting a large chuck at high speed or have a heavy piece of work on the lathe. No, Single phase 220v is two 110V single phase lines 120 degrees out of phase.OMG! "No, Single phase 220v is two 110V single phase lines 120 degrees out of phase" I think 180 degrees is what is meant... "One of the very nice things about a VFD is you can program the ramp up time. Instead of starting a single phase motor at 1800 rpm, the VFD will slowly start it with a linear increase in speed in 3 seconds or so (what ever you program it for). This really cuts down on the "FLA" required to start a motor. This can be important if you are starting a large chuck at high speed or have a heavy piece of work on the lathe." In the context of this topic, we're talking about starting/running 3 phase motors with 3 phase VFD's ***************************** This said I have experimented with inexpensive VFD's similar to the one in the link I posted on the other page... And did successfully run a 240 vac single phase [capacitor] furnace blower motor similar to what anyone would have in their home... The motor ran nicely and the total power draw was similar to running it on 240 ac. The VFD allowed the speed to be easily changed and the energy consumption was pretty much what I expected at less blower load. No over-heating or other ill symptoms... You need to re-examine your understanding of phases. Belushi is correct!  Three phases are 120 degrees apart. Whether it is A phase, B phase or C phase. Take any combination of two, you will always be 120 degrees apart. The reason one gets 220V single phase is measuring against the two 110V hot wires, you get 220V. It is not 'two phase' because there is only one measurement between phases. Three phase has three possible phase measurements. A+B, A+C and B+C This is as simplistic as I can make it. |
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You need to re-examine your understanding of phases. Belushi is correct!
Hmmm... You need to polish up your reading comprehension!!!!
Read what Belushi said again-- QUOTE "No, Single phase 220v is two 110V single phase lines 120 degrees out of phase" Three phases are 120 degrees apart. Whether it is A phase, B phase or C phase. Take any combination of two, you will always be 120 degrees apart. Not what Belushi referred to... See his quote above The reason one gets 220V single phase is measuring against the two 110V hot wires, you get 220V. It is not 'two phase' because there is only one measurement between phases. Belushi is talking about RESIDENTIAL WIRING in the context of this topic Three phase has three possible phase measurements. A+B, A+C and B+C No dispute here... This is as simplistic as I can make it. Quoted:
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Guys, stop embarrassing yourselves. This thread is like talking to GD about guns. FIFY
One of the very nice things about a VFD is you can program the ramp up time. Instead of starting a single phase motor at 1800 rpm, the VFD will slowly start it with a linear increase in speed in 3 seconds or so (what ever you program it for). This really cuts down on the "FLA" required to start a motor. This can be important if you are starting a large chuck at high speed or have a heavy piece of work on the lathe. No, Single phase 220v is two 110V single phase lines 120 degrees out of phase.OMG! "No, Single phase 220v is two 110V single phase lines 120 degrees out of phase" I think 180 degrees is what is meant... "One of the very nice things about a VFD is you can program the ramp up time. Instead of starting a single phase motor at 1800 rpm, the VFD will slowly start it with a linear increase in speed in 3 seconds or so (what ever you program it for). This really cuts down on the "FLA" required to start a motor. This can be important if you are starting a large chuck at high speed or have a heavy piece of work on the lathe." In the context of this topic, we're talking about starting/running 3 phase motors with 3 phase VFD's ***************************** This said I have experimented with inexpensive VFD's similar to the one in the link I posted on the other page... And did successfully run a 240 vac single phase [capacitor] furnace blower motor similar to what anyone would have in their home... The motor ran nicely and the total power draw was similar to running it on 240 ac. The VFD allowed the speed to be easily changed and the energy consumption was pretty much what I expected at less blower load. No over-heating or other ill symptoms... You need to re-examine your understanding of phases. Belushi is correct!
Hmmm... You need to polish up your reading comprehension!!!!
Read what Belushi said again-- QUOTE "No, Single phase 220v is two 110V single phase lines 120 degrees out of phase" Three phases are 120 degrees apart. Whether it is A phase, B phase or C phase. Take any combination of two, you will always be 120 degrees apart. Not what Belushi referred to... See his quote above The reason one gets 220V single phase is measuring against the two 110V hot wires, you get 220V. It is not 'two phase' because there is only one measurement between phases. Belushi is talking about RESIDENTIAL WIRING in the context of this topic Three phase has three possible phase measurements. A+B, A+C and B+C No dispute here... This is as simplistic as I can make it. |
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To address the OP, you are on the right track but you don't need this high dollar VFD to simply run a Bridgeport. A mill is not a demanding application compared to, say, PLC controlled water pumps feeding a distribution header without a surge tank and continuously changing speeds.
I used an Ebay $100 Chinese VFD for years with no problems. I now use a Hitachi I bought on sale off Ebay like this one: https://www.driveswarehouse.com/nes1-015sb-2689 for $200. I would contact Drives Warehouse (no affiliation) and get their recommendation. 3 HP 220V drives are common as dirt and there are too many to choose from. <massive snippage> Instead of starting a single phase motor at 1800 rpm with high amp draw and high acceleration, the VFD will slowly start a 3 phase motor with a linear increase in speed in 3 seconds or so... I obviously (?) meant a three phase motor. It's been a long day. You really appreciate the slow ramp up of a workpiece that may be unbalanced. In any case, wiring a VFD is easy for anyone with a bit of sense and ability to turn a screw driver. One of the markers of a maturing technology is the ease of using it. Noone has to be taught to use a cellphone, and almost anyone can wire a VFD. At my old job (really old), I had two 3 HP vfds sitting on the shelf the electricians fried wiring up one motor before they got it right. These guys wired up the whole plant and a PLC, so they were not neophytes. At least $10,000 each, they wired up 480V to ~20V DC control power and killed them. The manual was several books only an EE could understand. Now, they are almost plug and play. You have to RTFM if you want to change the default settings, but you don't need to. Just buy one and install it. For what it's worth, I ran one of those reviled Hungyaung VFDs on a Bridgeport for several years without any problems. The manual is online and not too tough to figure out. |
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This is what I'm looking at for my lathe and mill.
https://www.wolfautomation.com/products/ac-drives/ac-drive-3hp-230v-single-phase I'm thinking I can mount it on the cabinet in a vented box and run the operator panel up top to control it. I have no electrical experience, but from all my reading it looks like it should be pretty easy. |
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This is what I'm looking at for my lathe and mill. https://www.wolfautomation.com/products/ac-drives/ac-drive-3hp-230v-single-phase I'm thinking I can mount it on the cabinet in a vented box and run the operator panel up top to control it. I have no electrical experience, but from all my reading it looks like it should be pretty easy. That's a nice looking VFD
You can save ~$100 by going with the drive ref'd in the link on the previous page. Might be made in the same China factory. No need for a cabinet, just mount it away from chip contamination. Keep it simple... SO #12, 14, or #10 cord is your friend. I'd generally try to stick with 4 or 5 HP drives... A buddy bought a nice used mill about 500 miles away a couple years ago, I told him if he bought it I'd buy him the VFD to run it. That's the one I bought for him. We tore the head down over a couple days and replaced the belts and some parts. We hooked it up and it runs beautifully. His mill is a 3 HP Bridgeport clone with the little crank variable mechanical speed control and we simply set the VFD to output ~208 [depends on single phase line voltage going into the VFD] to a frequency of 60 Hz. The programming 'values' of the VFD linked to the previous page are easily available. I sold a small [ high quality] European lathe to a friend a while back and he put the same VFD on it. We used a $14 box store 230v 2 pole Square D surface mount breaker box to run the line voltage into, used two breakers in the box for protection, and then ran the power to the VFD and from it to the mill... Doesn't get any faster or less $$ than this. Huan Yang is specific with power protection instructions in their manual, however, this is the way we did it. There's a new VFD in the box on the shelf just looking for a place to go to work...
I also run a Clausing Metosa lathe, Bridgeport mill and Grob band saw, all 3 phase, in the mountains off a 25 kw Whisper Watt generator [way off grid] . I'm wondering if I can run all [not at the same time] from a 6 kw Wacker diesel light tower genny... |
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Actually from what I read, some houses have a three phase service with the phases sent to different houses or rooms (if in a large building). In this case measuring it will give you 208v instead of 220 or 240v.
From my understanding 3 phase power is 3 110v lines 120 degrees apart, and depending on how you wire them the voltage could be 110, 220 (or 208), 360, or 480v. By that I mean if you took any one of the phases and measured it against a neutral line you get 110v but if you measured across two of the phases it gives you a different voltage. This isn't Europe, where everything is 220v (meaning a true single phase 220v rather than split phase) meaning their 3 phase power allows even higher voltage... |
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I've been happy with the FM-50's so far. I have 4 of them running my lathe, mill and bandsaw. Other than increasing the rpm's on a couple they didn't require any programming and were pretty straight fwd to wire up. Getting the fwd-stop-reverse drum switch wired up correctly was the only part that had me scratching my head, but it wasn't really too bad.
I haven't found any place cheaper than factorymation http://www.factorymation.com/FM50-201-OC |
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Quoted: Actually from what I read, some houses have a three phase service with the phases sent to different houses or rooms (if in a large building). In this case measuring it will give you 208v instead of 220 or 240v. From my understanding 3 phase power is 3 110v lines 120 degrees apart, and depending on how you wire them the voltage could be 110, 220 (or 208), 360, or 480v. By that I mean if you took any one of the phases and measured it against a neutral line you get 110v but if you measured across two of the phases it gives you a different voltage. This isn't Europe, where everything is 220v (meaning a true single phase 220v rather than split phase) meaning their 3 phase power allows even higher voltage... You are right about the three phases running through neighborhoods, however only two legs are tapped out to residences. 3 phase is only run to a location after paying the POCO an outrageous installation fee along with a monthly surcharge. Voltage is controlled by transformers. Medium voltage is over 600volts and that is what is on the poles ... Typically 13kv Low voltage in the US is 460V, 230v, 208v and 120v ... all these can be 3 phase or single phase. Yes, I have seen and worked on 460 single phase. The transformer on the pole or your lawn is what steps it down to what you get from your meter. |
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In my neighborhood residential customers get one leg of the 3 phase power and it's center tapped to get the 120-120. I asked about getting 3 phase run into the house and it was going to be over 20k just to get the xformer installed on the pole. I decided I could buy a crapload of VFD's for that.
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You are right about the three phases running through neighborhoods, however only two legs are tapped out to residences. 3 phase is only run to a location after paying the POCO an outrageous installation fee along with a monthly surcharge. Voltage is controlled by transformers. Medium voltage is over 600volts and that is what is on the poles ... Typically 13kv Low voltage in the US is 460V, 230v, 208v and 120v ... all these can be 3 phase or single phase. Yes, I have seen and worked on 460 single phase. The transformer on the pole or your lawn is what steps it down to what you get from your meter. Quoted:
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Actually from what I read, some houses have a three phase service with the phases sent to different houses or rooms (if in a large building). In this case measuring it will give you 208v instead of 220 or 240v. From my understanding 3 phase power is 3 110v lines 120 degrees apart, and depending on how you wire them the voltage could be 110, 220 (or 208), 360, or 480v. By that I mean if you took any one of the phases and measured it against a neutral line you get 110v but if you measured across two of the phases it gives you a different voltage. This isn't Europe, where everything is 220v (meaning a true single phase 220v rather than split phase) meaning their 3 phase power allows even higher voltage... You are right about the three phases running through neighborhoods, however only two legs are tapped out to residences. 3 phase is only run to a location after paying the POCO an outrageous installation fee along with a monthly surcharge. Voltage is controlled by transformers. Medium voltage is over 600volts and that is what is on the poles ... Typically 13kv Low voltage in the US is 460V, 230v, 208v and 120v ... all these can be 3 phase or single phase. Yes, I have seen and worked on 460 single phase. The transformer on the pole or your lawn is what steps it down to what you get from your meter. Technically wrong again... At least one critical point... 
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The answer to the error in blue in the post above is contained in the link below...
Can anyone find it? You will learn a LOT if you try... 
http://www.science.smith.edu/~jcardell/Courses/EGR220/ElecPwr_HSW.html |
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Lemme guess...it's one leg stepped down to 240 and center tapped to get 2-120 lines?
I think it's a fairly common misconception that our houses are fed with 2 of the 3 phase legs. 120 deg. vs. 180 wouldn't work that well though. This reminds me of something I learned recently. I bought an old wells bandsaw a while back off of CL. I could clearly see it had a 240 volt plug so I assumed it was good to go but when I looked closer I noticed it had a 3 phase motor. It actually ran on that single phase 240 if you gave a little help starting. I'm sure it was not making it's rated power but I never would have thought to try it if it hadn't come that way. I did put a VFD on it anyway, it's nice to have speed control without changing belts. |
[ARCHIVED THREAD] - Phase converter options (Page 1 of 2)
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